L6 - Orchestration

The Orchestration layer (L6) coordinates multi-agent systems, routing requests, enforcing constraints, and ensuring reliable communication between agents.

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Overview

The Orchestration layer acts as the “traffic controller” for agent ecosystems, managing agent discovery, routing, load balancing, and failure handling.

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Core Responsibilities

Agent Routing

Direct requests to appropriate agent instances

Load Balancing

Distribute workload across healthy agents

Failure Handling

Circuit breakers and graceful degradation

Constraint Enforcement

Validate requests against Persona constraints

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Key Requirements

Routing & Discovery

Requirement	Description
Agent Routing	Route requests to appropriate agents
Agent Discovery	Dynamically discover available agents
Health Monitoring	Track agent health status
Version Compatibility	Route to compatible agent versions

Reliability Patterns

Requirement	Description
Circuit Breaker	Stop requests to failing agents
Load Balancing	Distribute requests evenly
Graceful Degradation	Fallback to degraded service
Bulkhead Pattern	Isolate failures to prevent cascades

Security & Authorization

Requirement	Description
Persona Enforcement	Validate against L5 constraints
Authorization	Authorize inter-agent calls
Trace Propagation	Pass trace context between agents

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Circuit Breaker Pattern

Configuration

{
  "circuit_breaker": {
    "failure_threshold": 5,
    "success_threshold": 3,
    "timeout_ms": 60000,
    "half_open_requests": 1,
    "monitored_errors": [
      "timeout",
      "service_unavailable",
      "internal_error"
    ]
  }
}

States

Closed

Normal operation
All requests pass through
Failures are counted

Open

Circuit tripped
All requests fail fast
After timeout, try half-open

Half-Open

Testing
Limited requests allowed
Success → Close, Failure → Open

Circuit Breaker Response

{
  "error": "circuit_breaker_open",
  "message": "Service temporarily unavailable",
  "agent_id": "agent-uuid",
  "failures": 5,
  "threshold": 5,
  "retry_after_ms": 60000,
  "fallback_available": true
}

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Load Balancing

Strategies

Round Robin

{
  "strategy": "round_robin",
  "agents": [
    {"id": "agent-1", "weight": 1},
    {"id": "agent-2", "weight": 1},
    {"id": "agent-3", "weight": 1}
  ]
}

Weighted

{
  "strategy": "weighted",
  "agents": [
    {"id": "agent-1", "weight": 50},
    {"id": "agent-2", "weight": 30},
    {"id": "agent-3", "weight": 20}
  ]
}

Least Connections

{
  "strategy": "least_connections",
  "agents": [
    {"id": "agent-1", "active_connections": 5},
    {"id": "agent-2", "active_connections": 12},
    {"id": "agent-3", "active_connections": 8}
  ],
  "selected": "agent-1"
}

Health-Based

{
  "strategy": "health_based",
  "agents": [
    {"id": "agent-1", "health_score": 0.95},
    {"id": "agent-2", "health_score": 0.6},
    {"id": "agent-3", "health_score": 0.88}
  ],
  "minimum_health": 0.7,
  "selected": "agent-1"
}

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Agent Discovery

Registry

{
  "agents": [
    {
      "id": "agent-uuid-1",
      "name": "Customer Support Agent",
      "version": "1.2.0",
      "capabilities": ["chat", "email", "ticket_creation"],
      "endpoint": "https://agent1.example.com",
      "health_endpoint": "https://agent1.example.com/health",
      "status": "healthy",
      "last_heartbeat": "2026-01-15T12:00:00Z",
      "metadata": {
        "region": "us-west-2",
        "environment": "production"
      }
    }
  ]
}

Discovery Query

{
  "query": {
    "capability": "chat",
    "version": ">=1.0.0",
    "region": "us-west-2",
    "status": "healthy"
  },
  "results": [
    {
      "id": "agent-uuid-1",
      "score": 0.95,
      "match_reason": "Exact capability match, healthy status"
    }
  ]
}

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Priority Queues

Configuration

{
  "queues": {
    "critical": {
      "max_size": 100,
      "timeout_ms": 1000,
      "priority": 1
    },
    "high": {
      "max_size": 500,
      "timeout_ms": 5000,
      "priority": 2
    },
    "normal": {
      "max_size": 1000,
      "timeout_ms": 30000,
      "priority": 3
    },
    "low": {
      "max_size": 2000,
      "timeout_ms": 60000,
      "priority": 4
    }
  }
}

Request with Priority

{
  "request_id": "uuid",
  "priority": "high",
  "agent_id": "target-agent",
  "payload": {...},
  "submitted_at": "2026-01-15T12:00:00Z"
}

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Bulkhead Pattern

Resource Isolation

{
  "bulkheads": {
    "critical_operations": {
      "max_concurrent": 10,
      "queue_size": 20,
      "timeout_ms": 5000
    },
    "batch_processing": {
      "max_concurrent": 5,
      "queue_size": 100,
      "timeout_ms": 300000
    },
    "general": {
      "max_concurrent": 50,
      "queue_size": 500,
      "timeout_ms": 30000
    }
  }
}

Bulkhead Response

{
  "error": "bulkhead_full",
  "message": "Resource pool exhausted",
  "bulkhead": "critical_operations",
  "current_usage": 10,
  "max_concurrent": 10,
  "queue_size": 20,
  "queue_usage": 20
}

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Graceful Degradation

Fallback Chain

{
  "primary": {
    "agent_id": "agent-1",
    "status": "unavailable"
  },
  "fallbacks": [
    {
      "agent_id": "agent-2",
      "status": "available",
      "degraded": false
    },
    {
      "agent_id": "agent-3",
      "status": "available",
      "degraded": true,
      "limitations": ["reduced_capabilities"]
    }
  ],
  "selected": "agent-2"
}

Degraded Mode Indicator

{
  "response": {...},
  "degraded_mode": true,
  "degradation_reason": "Primary agent unavailable, using fallback",
  "missing_features": ["advanced_analytics"],
  "estimated_quality": 0.85
}

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Persona Constraint Enforcement

Validation

{
  "request": {
    "agent_id": "agent-uuid",
    "capability": "database:write",
    "parameters": {...}
  },
  "persona_validation": {
    "passed": false,
    "violations": [
      {
        "constraint": "denied_capabilities",
        "value": "database:write",
        "action": "block"
      }
    ]
  },
  "action": "reject_with_error"
}

Override Logging

{
  "event": "persona_violation_attempt",
  "timestamp": "2026-01-15T12:00:00Z",
  "agent_id": "agent-uuid",
  "requested_capability": "dangerous_action",
  "persona_constraint": "denied_capabilities",
  "outcome": "blocked",
  "trace_id": "uuid",
  "severity": "critical"
}

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Trace Propagation

Envelope with Trace

{
  "envelope": {
    "id": "uuid",
    "trace_id": "distributed-trace-uuid",
    "span_id": "span-uuid",
    "parent_span_id": "parent-uuid",
    "timestamp": "2026-01-15T12:00:00Z",
    "source": {
      "layer": "L6",
      "agent_id": "orchestrator-1"
    },
    "destination": {
      "layer": "L4",
      "agent_id": "worker-agent-5"
    },
    "payload": {...}
  }
}

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Best Practices

1. Implement Circuit Breakers: Prevent cascade failures
2. Use Health Checks: Monitor agent availability continuously
3. Propagate Traces: Enable distributed debugging
4. Set Realistic Timeouts: Balance responsiveness and reliability
5. Implement Priority Queues: Ensure critical requests get processed
6. Use Bulkheads: Isolate resource pools
7. Plan for Degradation: Design fallback strategies
8. Log Routing Decisions: Maintain audit trail
9. Enforce Persona Constraints: Validate before routing
10. Monitor Continuously: Track latency, errors, and throughput

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Monitoring Metrics

Request Latency

P50, P95, P99 latency distributions

Error Rates

Circuit breaker trips, timeouts, failures

Load Distribution

Requests per agent, queue depths

Health Status

Agent availability, health scores

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Related Layers

• L1 - Runtime: Provides health check endpoints
• L5 - Persona: Defines constraints to enforce
• L7 - Protocol: Handles external agent communication
• Specification: Full requirements for L6 Orchestration

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